Many types of magnetic data storage media have been developed to store information. They include magnetic hard drives, magnetic diskettes, magnetic tapes, magnetic tape cartridges, hybrid magnetic media such as magneto-optical disks, and other magnetic media. Increasing data storage density and improving media quality and reliability are paramount goals in the development of new or improved types of magnetic data storage media. Cost reduction is another goal.
Magnetic data storage media generally function according to ferromagnetic or ferrimagnetic principles. For example, the surface of a magnetic recording medium may include a thin ferromagnetic layer, typically included in a thin film stack. The ferromagnetic material can be selectively oriented by a magnet in order to encode data on the surface of the medium. The orientations can then be detected and interpreted in order to read the recorded data.
Magnetic media typically include a substrate and one or more layers of ferromagnetic material deposited over the substrate. The substrate is typically a non-magnetic material that provides a support structure for the magnetic thin film stack. For example, glass and aluminum alloy substrates are commonly used in magnetic hard drives.
Plastic substrates, such as polymer substrates, polymer matrix substrates, polycarbonate substrates, and the like, can provide low-cost substrate alternatives to glass, aluminum, or other conventional substrate materials. However, plastic substrates often cause undesirable effects in the magnetic recording layers coated on the substrate.